250 CONTRIBUTIONS PROM MM NATIONAL HERBARIUM. 



Tin- \ ery delicate species is with some difficulty separated from < , a ntralit Ehrenb. 

 nli claims that its markings are so much finer that Ehrenberg could not have 

 >•■••?! iln'iii with his microscope. This is i 1 1» 1 < * •< 1 the difference But il is a question 

 if this offsets their close resemblance, in l>"th having a central rosette of very large 

 cells Burrounded by unusually fine markings, in both having the two peculiar mar 

 ginal processes which led Greville to class them as Eupodiscus, etc The separat ion 

 is ;ii leasl open to question. Greville's beautiful figure of /■.'. joneaiantu it inaccurate, 

 and Roper's figure emphasizes too Btrongly the radiating lii 



ind at stations 2807, 1516H . < ralapagos Islands, and off I "u er I alifornia. 



Coscinodiscus curvatulus ( Jrun. : Schmidt, Atlas pi. 57. f. SO, L878; /</. //..'. 



/. 6. 1888. Grun. Denkschr. Akad. Wien 48 s : 83. pl.4D./.8 t€ L884. Jan Diat. 



Exped. pi. .'../'. :. pl.S.f. .'. -:.s. pl.6.f. :. pi. .'<>./. /;. Cleve A Mall. 



typesno.57, 154, 162,164,276,319. Ratt.Proc. Roy. Soc. Edinb. 16: 186. 1889. 



De Toni, Syll. Alg. 2: L226. 1894. 



0d ontodiscus) curvatulus Grun. ; Cleve A Grun. Sv. Vet. Akad. Bandl. 

 17 : 113. pi. :../'. U • L880 Cleve in Nordensk. Vega Exped. 3: 188. 

 inodiscus szontaghii Pant. Beitr. Bacill. Ung. 1: 74. pi. 15. f. tSS } pi. 

 L886. 

 [n my specimens the curvature of the Fascicles is bo Blight as to be easily overlooked, 

 a characteristic which, though emphasized in the name, is unimportant and variable. 

 There can be do doubt thai this form and Actinocyclut curvatulus .Ian." axe the same 

 diatom except for the accident of a pseudonodule in the latter. I <1<> do1 regard the 

 figures byJaniscfa h as belonging here, though Rattray bo classifies them. II i> reference 

 to II. L. Smith type do. 99 as containing this Bpecies under the oameof OdorUodiscus 

 curvatulus Grun. is wrong, bo far as the slide I have is concerned. It comes from 

 Japan and is marked C. scintillans Grev., and although it Bhows abundant examples of 

 C. snh tills Ehrenb., which has Borne Blight resemblance to this species, it is a 

 quite distinct form, as Rattray points out. It is probable that Rattray's slide of 

 Smith"- do. 99 .-hows this Bpecies; but the reference is faulty as a general reference. 

 Pantocsek's figures of C. szontaghii are so utterly different from this species that they 

 are worse than useless. By reading his description it is, however, plain that Rattray 

 is correct in uniting this form with the above. It would be well for diatomists to 

 either forego the luxury of illustrations or make them Dear enough like the objects in 

 nature to be capable of recognition. 

 Found at stations 3604, K)22H, Bering Sea. 



Coscinodiscus decrescens (dun.. Schmidt. Atlas pi. 61. f. 8-10, 15. 1878. Grun. 

 Denkschr. Akad. Wien 48 J : 80. pi. S. C. ./'. //. 18. L884. Ratt. Proc. Roy. 5 

 Edinb. 16: 525. L889. De Toni, Syll. Alg. 2: L252. L894. 

 Rattray, followed by De Toni. includes in the above C. heteroporus Ehrenb. c and 

 jus Grun.d I think the assignment in Schmidt is much better. Rattray places 

 a question mark after Schmidt's plate 61, figure 10. which, if an example of this species, 

 must certainly be looked on as abnormal. Castracane has assigned this name to a 

 totally di Eferent diatom/ for which Rattray proposes the name C. minui ns. 

 Found at Btation 3361 II. Bering Sea. 



Coscinodiscus deformatus Mann. sp. nov. Pi.ati XI. VIII. ik.i res 1, 2. 



Valves Dearly flat for four-fifths of the radius, thence curving Blightly downward; 



network radially arranged, Bomewhat irregular at the center, hut with no umbilicus; 



hmidt's figures above with Ins pi. 57. f. •*'/. 

 '•.Ian. Diat. Gaz. Exped. />/. /../'. 6, />!. .;. 

 • Schmidt, Atlas />/. 61. f. <■ 7. L878. 

 '/ Sehmi.lt. Atlas pi. tlS.f. 7. 1888 

 « Castr. Rep. Voy. Chall. Hot. 2: i:><». pi. i.'.f. 14. 188G. 





